Signal system



March 18, l,1941. J. T. sTuBBlNs S IGNAL SYSTEM Filed April 28, 1938 2Sheets-Sheet 1 2 JOHN n m 4 n o w, n /M nwnln-Jblf. I.. d 3 f w .IW 3 .H4

March 18, 1941. J. T. sTuBBINs 2,235,123l

SIGNAL SYSTBH Filed April 28. 1938 2 ShlptS-Sheet 2 A HILF- l 5l 3mm":rome moms sruaams Patented Mar. 18, 1941 UNITED STATES PATENT OFFICE 11Claims.

This invention relates to a signal system and more particularly to animproved fluid pressure or impulse operated switch for the momentaryclosing of the energizing circuit of a signal device and to features ofconstruction of the iiuid pressure or impulse generating tube foractuating the switch.

The primary object of the invention is the provision of a rugged anddurable switch unit which may be readily and economically manufacturedand which is easily maintainablein serviceable condition by an attendantnot particularly skilled in such tasks. Although the unit isparticularly useful in signal installations in gasoline lling stationsto signal the'approach of vehicles to the dispensing apparatus, itshould be understood that it may be employed for other uses to which itmay be applicable. The invention resides in the various features ofdesign and arrangement of the elements constituting the switch and hasfor its further object the provision of such design and arrangement thatall the elements may be mounted on a. single stamped or cast casing withmeans Ito protect breakable elements, to expose adjusting and serv icingelements enabling manual engagement thereof, and to removably supportthe assembly on a wall or other suitable place.

A further object of the invention is to provide an improved constructionfor a fluid pressure impulse operated mercury switch in which the air inthe chamber containing the mercury is sealed against the admission ofmoisture or foreign matter which would tend to disrupt the sensitiveoperation of the switch.

Another object of the invention is the provision of improved means toclose and secure the free end of a collapsible tube when it is desiredto employ the tube as a generator for the fluid impulses required foractuating the switch.

These and other objects and advantages of the invention will becomeapparent from a consideration of the drawings and the following detailedspecification.

In the drawings:

Figure 1 is a plan view of a signal installation, embodying myinvention, as applied to a gasoline lling station;

Figure 2 is an elevational view, partly in section, showing a preferredform of switch embodying the principles oi' my invention;

Figure 3 is a sectional view of the apparatus of Figure 2 taken alongthe line 3-3 of Figure 2;

`Figures 4 and 5 are plan and sectional views,

respectively, oi the means for sealing and securing the end of thepulsa-tor tube; and

Figure 6 is a part sectional view of a modified form of switch embodyingthe principles of the invention.

Figure l illustrates a representative installation of Ithe 4signalsystem of this invention in which the pulsator I2 is extended across theinner driveway between the building I0 and the pump island II, over thepump island, and onto the driveway beyond the island. The tube issecured at its ends to 4the roadway by the cleats I3 and I4, cleat Ilbeing shown in detail in Figures 4 and 5 an-d cleat I4 being of similarconstruction but not swaged down sufficiently to collapse the tube. Theswitch proper I9 is mounted within the building I8, preferably on anouter wall thereof and is connected with the pulsator tube I2 by asmaller tube I5, a suitable reducer being positioned in the end of tubeI2 to make the connection. As shown schematically in Figure 1 -theswitch I9 controls the closing of the circuitpower source Il, switch I9,conductor I8, bell or other signal device I8 and battery I1 and theoperation is such that closing of the contacts of the switch I8energizes the bell or other signal device.

The switch of my invention consists generally of a casing 2l, a lead-intube 28, a U--tube 36 partially filled with mercury and contacts 34 and44. Casing 28 is of box-like character and has an open back and upperand lower flanges 2| and 22, respectively, in the plane of the back.Each of the anges 2i and 22 is provided with a key-hole slot 23 forengagement with a headed nail or screw fixed into the wall of thebuilding to support the switch and allow ready removal thereof for apurpose to be later described. Casing 2II is preferably cast and in theprocess an extra amount of material 24 is allowed to remain in onecorner thereof so as to provide the solid portion 24. To provide a ductthrough a part of the portion 24, a bore 25 is drilled into the portion24 from the side of the casing, which bore is subsequently sealed by aplug 26 held in place by the screw 2l. The lower wall of the casing 20and the lower wall of the bore 25 are provided with aligned aperturesfor the reception of the lead-in tube 28 and if considered desirable theupper end of tube 28 may be cemented or soldered in the upper aperture29.

Aligned apertures II and,30 are provided in the upper and lower walls,respectively, of the bore 25 at a location spaced from the tube 28 andanother aperture 38 is drilled in the upper wall of casing 20 at a pointspaced from the heavied portion 24. Fitting tightly into the aperture 38is the reduced portion of the member 39 which is of substantial diameterat its top, is provided with a threaded bore, and has a conical shapeddepression 4I! in its upper surface surrounding the upper end of thebore. U-shaped tube '36, preferably of glass. has one of its endscemented into the aperture 30 and its other end abutted against thelower end of member 39. As shown the reduced portion of member 39 andthe tube 36.have substantially equal external diameters and to hold thetube against the member a sleeve 4I, preferably of rubber, overlaps thends of the tube and member.

An insulating bushing 32, preferably of hard fibre, is fitted into theaperture 3| and into this bushing is threaded the screw 33 which carriesat its lower end the contact pin 34 extending down into the straight legportion of the mercury tube 36. A screw 43 carrying contact pin 44 isscrew threaded into member 39 and the pin extends down into the otherstraight leg portion of the tube 36. A quantity of mercury 31 is'placedin the tube 36 and this quantity and the position of the lower end ofpin 44 are so regulated that with the casing vertically aligned theupper surface of the mercury in the adjacent leg will be normally ljustshort of the lower end of the pin. Pin 34, however, is of sufiicientlength that it will be in engagement with the mercury substantially atall times. Due to the insulation 32 the screw 33 will be insulated fromthe pin 44 and consequently the casing unless the mercury 31 contactsthe pin 44. Screws 21 and 33 are therefore conveniently utilized as theterminals of the switch for connection with the leads I8 to the batteryor power source and the signal device.

In operation, an impulse of air or other iluid coming into the bore 25through tubes 28 and I5 from the pulsator tube I2, as when tube I2 iscollapsed by the wheel of a vehicle, will force the mercury around thebend of the U-tube and into engagement with pin 44. A circuit will thenbe established between the terminals 21 and 33 and the signal devicewill be energized. To

Alimit the length of such energization a. small aperture is provided inthe upper wall of bore 25 and into this aperture is placed the member 46which consists of a smaller diametered wire having a ball or bend ateach end, one above the upper surface of the casings top wall and theother within the bore. In case compression of the fluid is sustained bythe continued depression of the pulsator tube, the pressure will bereleased by the escape of fluid between the walls of the aperture andthe wire of member 46 and the contact between mercury 31 and pin 44 willbe maintained but momentarily. The balls or bends on the ends of thewire maintain the wire in position and provide a means to grip the wireto move the same and loosen any duct or foreign matter which tends toclose the aperture. After the parts are assembled the entire casing isthen preferably filled with tar, pitch or other suitable cementitiousmaterial (not shown) to securely hold the tubes 28 and 36 in positionand to prevent any tampering with or breakage of the tube operations.*4No elaborate machine work or other complicated processes are required.The ports required are simple, readily procurable and v the assembledunit as a whole may` be provided stlow cost.

During the operation of mercury switches, the mercury combines with themetal of the contacts and after a time an appreciable amount of theamalgam collects on the surface of the mercury to which is added otherimpurities which come into the tube. This seriously interferes with theproper operation of the switch and mustl be removed from time to time.In the servicing of the switch of this invention it is only necessary toremove screw 43. unhook the casing I9 from the wall, and tilt the sameto allow the fouled mercury to flow out. The impurities may then beseparated or a new supply of mercury poured into the tube, the conicalupper surface of the member 39 serving as a funnel for this purpose.Such servicing may be accomplished without disturbing any connections asthe flexibility of tube I5 enables the casing to be tilted for thepurpose. Contacts 34 and 44 which deteriorate fairly rapidly may bereadily replaced simply by unscrewing members 33 and 43 which carry thecontacts and replacing them with new ones. By furnishing a quantity ofmercury and new contacts along with the unit the unit may readily bemaintained in serviceable condition by anyone capable of followingsimpledirections. The structural features of the switch unit enablesthis to 'be accomplished.

Referring particularly to Figures 4 and 5, the cleat I3 used to secureand close the outer end of the pulsator tube I2 consists essentially ofa unitary plate member having a flat portion I3I adapted to engage thesurface of the roadway and a pair of integral lugs, |32,l adapted tobebent over the tube toward each other and to be swaged down tightly. Themetal of the cleat is of sulcient gauge to hold the end of the tubeclosed so that this end of the tube will be air tight. Flat portion I3Iextends beyond the end of the tube and is provided with an aperture |36to receive means for securing the same to the surface of a roadway.

Figure 6 illustrates a modified form of switch unit in which the chambercontaining the mercury is effectively sealed against the admission ofoutside air and impurities and in which the oscillation of the mercuryin the tube is dampened whereby recurrent contacting of the switchpoints is prevented and the life of the unit is increased. The casing50, having'flanges 5I with key hole slots 52, is generally similar tothe casing 2l of the first form described but in this modification theblock of material 54 extends entirely across the upper end of thecasing. Block 54 is drilled from both sides of the casing to provide thebores 55 and 56, the :bore 55 being sealed by a driven plug 59 and thebore 56 by the plug 51 conveniently held in place by the terminal screw58. Aligned apertures are drilled in the top and bottom wall of each ofthe bores and the two lower of these apertures are adapted to receivethe ends of the U-tube 15. The aperture in the upper wall of bore 56receives the hard fibre sleeve 10 in which is threaded the screw 12carrying conductor pin 13 which extends down into, the mercury 16 in thetube 15. 'Ihe aperture in the upper wall of the bore 55 receives themember 19 having a screw threaded bore extending therethrough and aconical shaped depression in its upper surface. Screw threaded 1I in themember 18 is the adjusting screw 8| which carries at its lower end thecontacting pin 82 extending downwardly into the tube 15.

A lead-in conduit 8| extends upwardly through an aperture in the lowerwall of the casing and is provided with a iianged upper end 52. Flange82- is clamped to the lower surface of block 54 by the screws 84 with aflexible diaphragm 85 and a spacing collar 63 positioned betweentheiiange and the surface. As shown, an aperture provides communicationbetween the upper side ot the diaphragm and the bore 58. A. similardiaphragm 85 is mounted adjacent the bottom wall of the bore 55, thecollars 88 and screws 85 serving to space and clamp the diaphragm 88.The space immediately above the diaphragm 88 communicateswith the bore55 by a suitable aperture.

With the parts assembled as shown in Figure 6, an impulse of air orother fluid coming through tube 8| will react on the diaphragm 65distending the same upwardly and transmitting the impulse to the airwithin the bore 58 and the adjacent leg of the tube 15. 'I'his forcesthe mercury 18 around the bend of the tube and into contact with the pin82, the diaphragm 86 distending downwardly to relieve the pressure inbore 55. Upon release of pressure on the under side of diaphragm 85either by loss through aperture 50 in tube 8| or |by return of thepulsator tube to its original shape, the pressures in bores 55 and 56will equalize and the mercury will return to its normal position asshown. The diaphragms cushion the impulses and prevent unduedisplacement of the mercury thereby preventing the surging or excessiveoscillation of the same. In normal use, as when a vehicle wheel runsover the pulsator tube, thecontact will be made but once. By sealing themercury chamber in the manner above described, foreign matter `andmoisture are prevented from entering the same and consequently theswitch is not so apt to develop trouble and it will have a' longer life.

Conductors connecting the energy source and the signal device areconnected with the screws 58 and 12 and as in the switch first describedthe conducting pins 13 and 82 are readily replaceable and the unit isotherwise readily serviced in a simple manner and without the aid of anyspecial tools.

The above specifically described embodiments of my invention should beconsidered as illustrative only as obviously many changes may be madetherein without departing from the spirit of my invention, the extent ofwhich is indicated by the appended claims.

I claim:

1. A circuit closing device comprising a casing having side walls, topand bottom walls, and a front wall, one of said walls being of increasedthickness within said casing and being provided with a bore, a tubeextending through an aperture in another of said walls and communicatingwith said bore, aligned apertures in opposing walls of said bore, aU-tube having one leg thereof received within one of said apertures, aninsulating sleeve in the other of said apertures, a. screw threaded intosaid sleeve, a current conducting pin carried with said screw andextending downwardly into said leg of the U-tube, a quantity of mercuryin said U-tube, and means in the other leg of the U-tube adapted to becontacted by said mercury upon movement thereof,

2. A casing for a iiuid pressure responsive circuit closing devicecomprising a unitary member having side walls, top and bottom walls, anda front wall, one of said walls being of increased thickness Within thecasing and being provided with a bore for the passage of fluid underpressure, an aperture in a side wall'of said bore, an aperture inanother` wall ot said casing aligned with said first mentioned aperturewhereby a tube may be extended from outside said casing to Within saidbore, and means on said casing to releasably'support the same.

3. A circuit closing device comprising a unitary casing having anintegral block beneath a portio'of its top wall, a horizontallyextending bore in said block, means to conduct uid under pressure tosaid bore, vertically aligned apertures in the top and bottom walls otsaid bore, an aperture in said top wall at a point spaced from saidblock, an internally bored and threaded member extending through saidlast mentioned aperture and being provided above 'said wall with anenlarged portion having a conical-shaped depression in its uppersurface, a U-shaped tube having one of its ends positioned in theaperture in the bottom wall of said lbore and its other end abutting thebottom surface of said member, a sleeve overlapping the bottom portionof said member and the adjacent upper portion of said tube, aninsulating bushing in the aperture in the top wall of said bore, a screwthreaded into said bushing and carrying at its lower end a pin extendinginto said U-tube, a second screw threaded into said member and carryingat its lower end a second pin extending into said U- tube, and aquantity of mercury in said U-tube.

4. A circuit closing device comprising a-unitary casing having a hollowblock integral therewith, aligned apertures in the top and bottom wallsof said block, a U-tube having one of its ends positioned in the lowerof said apertures, an insulating bushing in the other of said apertures,a current conducting member held by' said insulating bushing andextending downwardly into said tube, means to conduct fluid underpressure to the space within said block, a quantity of mercury withinsaid tube, and means extending into said tube from the other end thereofadapted to be contacted by said mercury uponmovement thereof.

5. A circuit closing device for a signaling system of the kind employinga pulsator tube and a fluid connection between said tube and devicecomprising a pressure chamber in communication with said fluidconnection, a pair of switch contacts, means responsive to the pressurewithin said chamber to close said contacts, an aperture in the wall ofsaid chamber, a member having less cross-sectional area than saidaperture extending through said aperture, andimeans connected with saidmember beyond each end of said aperture to normally prevent removal ofsaid member.

6. A circuit closing device comprising a duct sealed at either end by adistensible diaphragm, means to conduct fluid under pressure to theouter side of one of said diaphragms, the outer side of the other ofsaid diaphragms being open to the atmosphere and means within said ductresponsive to movement of the fluid within said duct in a direction awayfrom said iirst specifically mentioned diaphragm to close a circuit.

7. A circuit closing device comprising a duct sealed at either end by adistensible diaphragm, means to conduct fluid under pressure to theoutter side of one ot said diaphragme. the outer side of the other ofsaid diaphragme being open to the atmosphere, a fixed contact withinsaid duct. and a body of mercury within said duct movable intoengagement with said fixed contact by the pressure within that portionor said duct adjacent the said one of said diaphragme generated byinward movement of said diaphragm.

8. A circuit closing device comprising a duct closed at either end by adistensibie diaphragm, means to conduct uid under pressure to the outerside of one of said diaphragms, the outer side of the other of saiddiaphragms being open to the atmosphere, and means within said ductresponsive to the inward movement o! said pressure actuated diaphragm toclose a circuit.

9. A circuit closing device comprising a unitary casing having spacedapertures in its top wail, a U-shaped tube having its ends aligned withsaid apertures, a quantity of mercury in said tube. means to conduct animpulse of fluid under pressure to one of the legs of said tube, anelongated means extending through said apertures and into the legs ofsaid tube to contact said mercury, the two elongated means beinginsulated from each other.

10.A circuit closing device comprising a duct sealed at either end by adistensible diaphragm, means to conduct duid under pressure to the outerside of one ot said diaphragme. the outer side oi the other oi saiddiaphragme being open to the atmosphere, said duct including a U- shapedportion intermediate said dlaphragms. a quantity of current conductinguid in said por@ tion, means to conduct current to said quantity of uid,and means in said duct to conduct current from said quantity ot iiuidupon the'application of pressure to one of said diaphragms.

11. A circuit closing device for a signaling system having a conditionresponsive iuid pressure generating means comprising a casing adapted tobe detachably connected to a wall or other suitable support, said casingbeing provided with a portion projecting outwardly from said wall orsupport. a U tube mounted on said portion, a body of mercury and switchcontacts in said tube, means to connect one leg of said tube with saidiluid pressure generating means, said casing com.. prising a unitarycup-shaped member having anges in the plane o! its open end forengagement with the wall or support, the U tube being housed within thecup.

JOHN THOMAS STUBBINS.

